TouchEvent

Declaration

interfaceTouchEvent

Overview

The system continually sends TouchEvent objects to an application as fingers touch and move across a surface. A touch event provides a snapshot of all touches during a multi-touch sequence, most importantly the touches that are new or have changed for a particular target. A multi-touch sequence begins when a finger first touches the surface. Other fingers may subsequently touch the surface, and all fingers may move across the surface. The sequence ends when the last of these fingers is lifted from the surface. An application receives touch event objects during each phase of any touch.

The different types of TouchEvent objects that can occur are:

touchstart

Sent when a finger for a given event touches the surface.

touchmove

Sent when a given event moves on the surface.

touchend

Sent when a given event lifts from the surface.

touchcancel

Sent when the system cancels tracking for the touch.

TouchEvent objects are combined together to form high-level GestureEvent objects that are also sent during a multi-touch sequence. See GestureEvent for details on GestureEvent objects and an example of the events sent for a two finger multi-touch gesture.